Architectural 5.1
Structural 5.10
Mechanical 5.12
Electrical 5.19
Building Systems and Components
Building systems are those primary elements which together define the shape, utility, and comfort of built space. They are classified by discipline: Architectural, Structural, Mechanical, and Electrical. These systems must be planned and designed in concert; individually, they are composed of lesser components, such as interior framing systems, air-conditioning units and plumbing fixtures. Knowledge of how these systems coordinate and interconnect, as well as familiarity with the individual component systems and disciplines is essential for the successful integration of these items.
Their coordination is critical to the overall appearance and operation of the completed interiors project.
Architectural
Architectural systems define the volumes and functions of a building. Every project begins with a statement of needs, developed by the end-user and designer, from which an initial space plan is developed. This plan sets the course for the rest of the project, including the locations of mechanical rooms, electrical closets, plumbing shafts, and data/communications shafts within the space. The development of other systems follows the architectural lead. Architectural systems are primarily concerned with enclosure (walls, roof), and definition (partitions, floors, ceilings). For interiors, definition is the primary concern.
The primary system of organizing or defining architectural space is the partition. Partitions (or more commonly "walls") define and divide space. In modern construction, the stud-framed partition, either metal or wood, is most prevalent. In commercial construction metal is most frequently used (Fig. 1). A typical partition consists of studs at 400 mm (16 inches) on center with gypsum wallboard on each side. The partition may bear directly on structure, or sit on the finished floor, and may extend to the ceiling or beyond - depending upon various requirements placed on the wall to control thermal variance, acoustics, firespread, etc. Its thickness may range from 65 mm (2-1/2 inches)
Spatial Definition is accomplished primarily by establishing a series of planes in space which organize our understanding of a place.
to more than 300 mm (12 inches) depending on what services are contained within, or what other
requirements are placed upon it. Stud partitions are basically hollow, thus providing opportunity for distribution of power, communications and tempering systems. In addition, they may be filled or insulated for increased thermal and acoustical performance.
Partitions may be pre-constructed or demountable—built in factories to modular sizes and shipped to a jobsite for installation. In addition to gypsum wallboard and wood or metal studs, partitions may be glass, wood, metal, or masonry. In each case, the only requirement is that the partition satisfy the demands placed upon it, and that the existing structure be able to support it.
Floors and ceilings also define architectural spaces.
Although partitions in the strict sense of the word, they are not typically referred to as partitions except in specific instances. (When partitioning off a space, the ceiling is a part of that partition and must therefore meet code partition requirements; however, it is still generally referred to as the ceiling.)
Together, floor and ceiling planes make up the largest share of an interior environment. Floors are typically flat but level changes can be added for spatial separation or aesthetic variety. Floors in commercial structures are
Fig. 1 Stud partition
typically constructed of concrete, or concrete on metal deck. This can be left exposed, as in industrial facilities, or totally covered with another floor covering such as carpeting, wood flooring, or vinyl tile.
Many times, ceilings are overlooked in the design of an interior environment. They are left bare and used simply as overhead protection. The ceiling is, however, an important part of the overall design of an environment.
By changing the angle of the ceiling plane, piercing it with windows, or adding soffits and coves, the designer can make the ceiling an active part of the design. The
ceiling can be left smooth or fitted with light fixtures, vents and decorative elements. Ceilings can be constructed from a variety of materials: plaster and lath, gypsum board, wood, suspended ceiling systems (Fig. 2), metal, or glass.
Millwork, as a part of architectural systems and componentry, encompasses standing and running trim, paneling, doors, and windows. Broadly speaking, millwork is any ready-made product that is manufactured at a wood mill or woodworking plant.
This is generally construed as piece goods. For a
Fig. 2 Suspended ceiling
discussion of wood types, and casegoods construction, see chapter seven. For a discussion of wood finishes, see chapter six.
Architectural millwork has three primary functional origins. The first is one of necessity: doors and windows have traditionally been constructed from wood due to its wide availability and ease of workability. Millwork is also a decorative solution to concealing the construction of a space. Wood-paneled rooms were originally conceived as elegant woodgrained renditions of the expressed structure of a space. Finally, millwork serves a use which is a cross between the decorative and the functional, depending upon the intent of the user:
baseboards, door trim and ceiling moldings are often the most expeditious way to close the joint that exists between two construction elements. Whether the piece becomes decorative or not is the designer’s choice.
Standing and running trim refers to two distinct classes of wood trim. Standing trim refers to fixed length trim such as door and window casing, window stoops and door thresholds. Running trim is continuous trim used to form baseboards, cornice moldings, chair rails, etc. Almost any shape is available in wood trim, especially if custom trim is an option. Each millwork house or trim manufacturer offers its own standard profiles, which are then the most readily available and economical.
Paneling is the term used for wood applied to a wall surface. It may be assembled from rails and panels of solid wood, or from plywood. Simply stated, paneling is any flat assembly of wood members applied to a vertical surface.
Doors (which, like walls and ceilings, are an architectural space organizer) are typically one of two kinds. The flush door is available in solid or hollow core construction. Flush doors are typically constructed of two veneered faces glued to a frame which contains either a honeycomb core of kraft paper (hollowcore); or a solid core of industrial board or laminated wood staves (solid core). Solid core construction is heavier, stronger, and more resistant to the passage of sound than hollow core doors, and is generally more expensive. Flush doors
Millwork may be functional or decorative, largely dependent upon the designer’s intent.
of either type are available in a variety of veneer species, the least expensive of which are intended to be painted.
Stile and rail doors are traditionally constructed of a wood framework of vertical (stile) and horizontal (rail) members infilled with shaped wood panels. Today the look of stile and rail doors is available in traditional construction, stamped metal, stamped hardboard, or veneered structural plastic. The traditional wood construction stile and rail door is still the most appropriate for commercial use where the look of stile and rail is desired. Stamped metal and structural plastic tend to be limited in use to exterior applications.
Stamped hardboard is simply a shaped hollow core door used primarily for economy in residential applications.
Many of the problems typically associated with stile and rail doors, due to movement of the panel and loosing of joints, have been eliminated or minimized with new construction technologies and materials, and as a result, a quality stile and rail door today is nearly as stable as a solid core door.
Construction and Life Safety
In addition to giving definition to a space, the architect or interior designer needs to provide for the safety of the occupants within the space. The means of construction contribute to the total life safety package. Walls, floors, ceilings, doors, and windows are all required to provide protection from fire, environmental contaminants, and the elements. Standards for construction, as published in building codes and technical manuals dealing with specific construction materials and techniques, have been rigorously tested and confirmed to meet stringent requirements. Even minor variances in the construction of a building can change its resistance to these factors in unforeseen ways.
Acoustics
Besides providing protection, the envelope that defines interior space also affords a tempering of the environment, through acoustic and thermal control. Both sound and heat are transferable energy. Thermal requirements for an interior space are generally contained within the shell of the structure and will not be
dealt with here. Acoustic control is the more pertinent topic.
Acoustics as an environmental variable significantly impacts the human impression of an interior environment. Productivity, speech intelligibility, privacy, safety, positive user attitude and response, and environmental “comfort” all depend on proper acoustic design. The interior designer is concerned with reducing unwanted noise and preserving desirable sound in a space. Enhancing the quality of communication through the use of reflective surfaces, and reducing undesirable noise through the use of absorptive surfaces is achieved by the specification of finishes, furnishings, equipment, and specially designed assemblies. Sound can be controlled in three ways.
• Eliminate the source (Fig. 3).
• Isolate the source—provide a barrier between the user and the source (Fig. 4).
• Mask the offending sound—if not possible to isolate the sound, minimize its impact on the user (Fig. 5).
In addressing acoustics and communication within an environment, it is necessary to consider levels of speech intensity. For example, intensity levels are likely to be greater among occupants over the span of a conference table than over an executive desk in a private office.
Optimum planning for open areas will include consideration of background noise, and use of absorptive ceiling, flooring, and furnishing elements. With enclosed space, the noise reduction capabilities of construction between rooms significantly influences speech privacy.
Sound is measured on a relative scale, in decibels (dB or dB), with 0 dB being the threshold of audibility, and 130 dB the threshold of pain. In an office, a general noise level of 45 to 55 dB is considered satisfactory.
This level will help reduce the distraction associated with squeaky chairs, opening and closing drawers, and ringing phones. It also allows for easy conversation in normal tones at close range. Other noise levels of varying activities are given in the chart shown in Figure 6.
Fig. 3 Elimination
Fig. 4 Isolation
Fig. 5 Masking
In dealing with acoustics in an environment two major topics need to be addressed: excessive noise and sound
transmission from one area to another.
Excessive noise within an environment includes opening/closing drawers, squeaky chairs, printers or
Pressure Level in Decibels
Example Subjective Impression
140 Jet Plane Takeoff (Short Exposure Can Cause Hearing Loss)
130 Artillery Fire Deafening (Threshold of Pain)
120 Jet Plane (Passenger Ramp)
110 Hard Rock Band (Threshold of Discomfort)
100 Power Lawnmower Very Loud (Intolerable for Phone Use)
90 Kitchen Blender
80 Noisy Office
70 Average Street Noise Loud
60 Normal Conversation Usual Background
50 General Office
40 Private Office Noticeably Quiet
30 Quiet Conversation
20 Whisper Very Quiet
10 Human Breathing
0 dB Intolerably Quiet (Threshold of
Audibility)
Fig. 6 Decibel Pressure Levels of Common Environmental
copiers, shuffling feet, etc. Excessive noise is all noise beyond that which provides an ambient level conducive to normal conversation. All surfaces within an interior can contribute to the Noise Reduction Coefficient (NRC) of a space. The NRC indicates how well a material will absorb sound on a scale of 0.00 to 1.00, with 1.00 being total absorption. The most common use of the NRC rating appears on ceiling materials. Most acoustic ceilings have NRC ratings between 0.50 and 0.90. The minimum recommended NRC rating for acoustic material in open plan offices is 0.80. Generally, the thicker, softer and more porous a material is, the greater
its NRC. The table in Figure 7 shows NRC levels for different interior materials.
Sound transmission deals with noises coming outside the occupied space. Typically sound transmission is dealt with during construction, through use of heavy building materials or double-wall construction. However, once the structure is complete, interior materials can give some improvement. The Sound Transmission Class (STC) indicates a material’s effectiveness in preventing sound transmission. The following table gives STC
Material NRC Bare Concrete Floor .05
Tile or Linoleum on Concrete .05 Carpet - 1/8" (3 mm) pile .15
Carpet - 1/4" (6.5 mm) pile .25
Carpet - 3/8" (9.5 mm) pile .37
Plaster Ceiling .45
Metal Pan Acoustic Ceiling .60 Systems Furniture Partition Surface .65
Carpet over Padding .65
Suspended Mineral Board Acoustic Ceiling .90
Fig. 7 Noise Reduction Coefficients of Common Finish Materials
ratings for varying materials; the higher the number, the better noise is blocked (Fig. 8).
The selection of materials for wall finishes, floor covering and ceilings must be coordinated to assure the desired level of acoustic control. Additionally, providing window coverings over large expanses of interior/exterior window wall glazing, and/or the installation of an electronic sound masking system will contribute to a successful level of acoustic control.
Among interior surfaces, the ceiling is the largest surface affecting noise reflection and absorption. In a standard office environment, the ceiling system should produce minimal sound reflectance. Systems that reduce sound reflectiveness are flat, absorbent ceiling panels, baffles and vaulted ceiling components. The size, shape, number, and placement of luminaires, as well as the shape of other hard-surface ceiling components such as diffusers, will increase the specular, or mirror-like, reflectiveness of the ceiling.
Material STC 5 mm (3/16") Plywood 19
Open-Plan Furniture Screen Panel (Typical) 21
16 mm (5/8") Gypsum Wallboard 27
22-Gauge Steel Plate 29
120 mm (nominal 2 x 4 ) Wood Stud Partition with One Layer 16 mm (5/8") Wallboard Each Side
37
170 mm Staggered Wood (nominal 2 x 4) Stud Partition with One Layer 16 mm (5/8") Wallboard Each Side
45
150 mm (6") Concrete Block Wall 46
150 mm (3-1/2:") Steel Stud Partition with Two Layers of 16 mm (5/8") Wallboard Each Side
55
Fig. 8Sound Transmission Coefficient of Common Building Assemblies
The floor is the second largest surface area for absorption or reflectance of sound. Carpeting will absorb a significant amount of impact sounds such as chair movements and shuffling feet as well as other office sounds. Cut pile carpeting absorbs more sound than loop pile carpeting; the greater the pile height and weight in cut pile carpets the greater the absorption.
The degree of treatment of wall surfaces depends on the intensity of the sound and the distance between the sound source and the surface. Generally, fewer vertical surfaces will have to be treated in a large room than a small one. The larger room has more volume to dissipate the sound and a greatly diminished wall to floor and ceiling surface ratio. Besides providing sound insulation within partition cavities, draperies covering windows or walls, panels of acoustic material hung on the walls, and acoustic material (panels and paints) applied to interior walls all are effective treatments in minimizing noise reflectance.
Structural
The structure is the skeleton of the building. The structural plan is often the first component reviewed by the designer, especially if interior wall relocation is being considered. The structural module, a geometric increment, is the base unit of organization utilized by the structural engineer in setting the structural system for a building. In addition to providing definition and clarity to the work of the structural designer, the resultant expression of the module—whether the repetitive spacing of ceiling joists or pans, or the regular placement of columns—provides a framework for the organization of the interior spaces. The overlaid spatial organization should integrate the lighting layout, ceiling grid, mechanical systems, partition planning, and furniture layout within this larger framework. Interior columns that define bays may be concealed by integration into partitions, or left exposed within the space and used to provide reference points for the occupants, or to define specific zones of activity.
The paradigm of the modern building is the simple Maison Domino (Fig. 9), Le Corbusier's diagram of the
Fig. 9 Maison Domino
regularly spaced columns and floor plates. An actual structure may not be much more complicated, with greater definition given only to the structure of the floor (larger spans may require a framework of joists and beams to support the floor slabs), and to lateral bracing (to prevent the structure from rocking under wind load or other horizontal force).
The primary structural information an interior designer must be aware of is what elements of the space provide the structural support, and how do those elements interrelate (Fig. 10). A few basic guidelines will help.
• Modern structures are primarily steel or concrete. The choice is based upon the availability of materials and structural constraints of the individual materials.
• Vertical support members, columns and structural walls carry loads, and are generally not modified after construction.
• Beams may be solid or trussed construction. Trussed beams have openings in them which may be used for the passage of building systems. Solid beams may be penetrated for such passage, but this is primarily done in the initial design of the building and seldom after construction. Beams join columns in perpendicular
Fig. 10 Modern construction members
connections critical to the overall integrity of the structure. Whenever modifications are to be made to a beam, it is imperative that a structural engineer be consulted.
• Joists are smaller beam elements that carry the floor loads to other, larger, beams. The rules stated above for beams also apply to floor joists.
• Floor slabs are generally concrete, either formed over a temporary framework, or over a steel pan which remains in place and provides some portion of the structural capacity of the floor. Services may be run through floors with relative ease. Large openings may require the addition of supplementary joists to support the edges of the opening. Smaller openings require coordination to avoid interference with the supporting structure.
Additional small openings for the passage of plumbing and electrical services are commonly required during the fit-out of spaces.
• Structural systems may not always be what they appear to be. A simple stud partition which terminates at the ceiling may not be a structural member, but it may in fact conceal lateral bracing for the structure. As with all systems discussed in this chapter, elements exist which may be concealed; and before proceeding with any significant reorganization of a space, it is best to ask the opinion of a structural engineer or architect.
Mechanical
The mechanical systems in a building are designed to perform a variety of functions. They are responsible for heating, ventilating and cooling the environment as well as supplying fresh water and disposing of waste water.
The designer must have a basic knowledge of these systems and equipment functions to understand their impact on interior design.
Heating, Ventilating and Air Conditioning (HVAC)
HVAC system concerns for the interior designer relate not only to the visible elements such as radiators, convectors, registers, outlet grilles, or ducts—which are the end nodes of the systems—but also to the infrastructure that supplies those elements. Two primary
types of systems exist: central and local. Central systems provide either tempered air or water throughout the facility from a single location. Local systems are generally stand-alone and receive their energy via gas or
types of systems exist: central and local. Central systems provide either tempered air or water throughout the facility from a single location. Local systems are generally stand-alone and receive their energy via gas or